2,4,6-trinitrotoluene (TNT) - OEHHA

1 

2,4,6-Trinitrotoluene (TNT) 

CAS No. 118-96-7 

Formula: C6H2(NO2) 3CH3 MW: 227.1 

Chemical Class: polynitroaromatic hydrocarbon 

Office of Environmental Health Hazard Assessment

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Use & Occurrence of TNT 

• Explosives in military & industrial applications 

(munitions, coal/mineral mining, deep well/ 

underwater blasting, building demolitions) 

• Chemical intermediate 

• In soil & surface/ground water near sites of use 


3 

Carcinogenicity Studies of TNT 

• Studies in humans 

—One ecologic study 

—One case-control study 

—One cohort study 

—Several case reports 

• Studies in animals 

— Two-year dietary studies in rats of both sexes 

— Two-year dietary studies in mice of both sexes 


4 

Environmental TNT Contamination and 

Leukemia in Germany 

Ecologic incidence rates study (Kolb et al., 1993) 

• Apparent cluster of myeloid leukemia in city of Stadtallendorf 

confirmed 

— AML men RR 3.5 (CI 1.4-8.5) 6 cases in city, 28 in unexposed county 

— AML women RR 3.2 (CI 1.4-7.2) 7 cases in city, 29 in unexposed county 

— CML men RR 9.1 (CI 3.5-23.4) 7 cases in city, 13 in unexposed county 

— CML women RR 1.3 (CI 0.2-10.3) 1 case in city, 10 in unexposed county 

Population-based case-control study (Kilian et al., 2001) 

• Increased risk found for one neighborhood 

— All leukemia OR 5.1 (CI 1.1-23.8) 4 cases, 3 controls exposed 

— CML only OR 9.0 (CI 1.1-72.1) 3 cases, 1 control exposed 


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TNT-Exposed Munitions Workers and 

Liver Cancer in China 

Historical cohort study (Yan et al., 2002) 

• Incidence compared to non-exposed workers: 

RR 3.46 (p < 0.01) 

• Mortality compared to Chinese national rates for cities: 

RR = 2.71 (p

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Case Reports of Liver Cancer and 

Leukemia in Workers Exposed to TNT 

• Liver Cancer 

— 1 case in Garfinkel et al. 1988 

— 9 cases in references cited by Yan et al. 2002 

• Liu 1986 (4 cases) 

• Wang 1991 (3 cases) 

• Yang and Xie 1995 (1 case) 

• Fu and Shang 1998 (1 case) 

• Leukemia 

— 2 cases in references cited by Yan et al. 2002 

• Wang 1991 (1 case) 

• Liu et al. 1995 (1 case) 


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Tumors in Female F344 Rats Fed TNT 

for Two Years (Furedi et al., 1984a) 

Urinary 

bladder 

Lesions 

TNT dose (mg/kg/day) 

0.0 0.4 2.0 10.0 50.0 

Papilloma 0/54 0/54 0/55 1/55 5/55* # 

Carcinoma 0/54 0/54 0/55 0/55 12/55** # 

Papilloma & 

carcinoma 

0/54 0/54 0/55 1/55 17/55** # 

* p

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Tumors in Female B6C3F1 Mice Fed TNT 

for Two Years (Furedi et al., 1984b) 

Lesions 

leukemia/ malignant 

lymphoma of the spleen 

TNT dose (mg/kg/day) 

0.0 1.5 10.0 70.0 

** p

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Summary of Carcinogenicity 

Studies in Rodents 

• Rare urinary bladder carcinomas and papillomas 

in female F344 rats 

• Leukemia & malignant lymphomas of the spleen 

in female B6C3F1 mice 

• No treatment related tumors observed in male 

rats or male mice 


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Other Relevant Data 

• Pharmacokinetics & Metabolism 

• Genotoxicity 

• Structure Activity Comparisons with 

Proposition 65 Carcinogens 


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Pharmacokinetics & Metabolism of TNT 

• Absorption: GI tract, skin & lungs 

• Distribution: Primarily to the liver, kidneys, 

lungs & fat 

• Elimination: Primarily via urinary excretion 

• Metabolism: 

-Nitroreduction of aromatic nitro groups to 

hydroxylamino derivatives 

-Oxidation of methyl group to benzyl alcohol & 

benzoic acid derivatives 


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Metabolism 

The major metabolic 

pathways of TNT 

(adapted from Bolt et 

al., 2006). 


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TNT Genotoxicity : Bacterial Systems 

Salmonella typhimurium Reverse Mutation Assays 

•Positive in strains TA98, TA1537, TA1538 

& TA100 

-Frameshift & basepair substitution 

-Presence or absence of metabolic activation 

-Requires nitro reductase, o-acetyltransferase 

Escherichia coli SOS Chromotest 

•Positive (human placenta microsomal system) 

•Negative (rat liver S9) 


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TNT Genotoxicity: Mammalian In Vitro Systems 

• Rat 

—Negative: in vitro liver UDS assay 

• Mouse 

—Positive: P388 lymphoma TK locus mutation 

assay (-S9) 

• Hamster 

—Positive: CHO-HPRT mutation assay (+S9) 

—Negative: V79-HGPRT mutation assay 


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TNT Genotoxicity: Mammalian In Vivo Systems 

• Rat 

—Negative: liver UDS assay 

—Negative: bone marrow cytogenetic damage 

—Positive: oxidative DNA damage (8-oxodG) in 

sperm cells 

• Mouse 

—Negative: bone marrow micronucleus assay 


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TNT Genotoxicity in Humans 

• No difference between TNT-exposed and control 

workers in frequency of chromosomal aberrations 

(CA) in peripheral blood lymphocytes 

� Among TNT-exposed workers 

—Increased CA in NAT1 rapid vs. slow acetylator 

genotype 

� Among TNT-exposed workers with NAT1 rapid 

acetylator genotypes 

—Increased CA associated with GSTM1 null or 

GSTT1 null genotypes 


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Genotoxicity of TNT Metabolites 

2-ADNT 4-ADNT 2,4-DANT 2,6-DANT 

Salmonella mutation 

assays (TA 98, TA100) + + + + 

CHO-HPRT 

mutation assay 

V79-HGPRT 

mutation assay 

4-NHOH-DNT 

- + (S9) - + (weak) 

- + (weak) - - 

- Positive: in vitro oxidative DNA damage (8-oxodG); 

cleaves DNA at sites with consecutive guanines 


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Urine Mutagenicity 

• Rats treated with TNT 

—Positive in Salmonella 

• Humans exposed to TNT 

—Increased mutagenicity in Salmonella of 

urine from exposed as compared with 

unexposed controls 

—Higher in NAT1 rapid vs. slow acetylators 


Structure-Activity Comparisons 

with Proposition 65 listed carcinogens 

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2,6-Dinitrotoluene 2,4-Dinitrotoluene 2-Nitrotoluene 

Rats: liver (♂) Rats: skin (♂), 

liver & mammary (♀) 

Mice: kidney (♂) 

Rats: mammary, liver & 

lung (♂), mammary & liver 

(♀) 

Mice: intestinal (♂, ♀) 

DNA and protein binding DNA and protein binding DNA and protein binding 

Office of Environmental Health Hazard Assessment 

TNT

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Potential Mechanisms of 

Carcinogenicity 

• Genotoxicity 

- Mutation 

- Induction of oxidative DNA damage 


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Authoritative Body Reviews 

• US EPA (1993) 

—Reviewed animal studies by Furedi et al. (1984a,b) 

—Did not include any human studies 

—Did not include several studies on metabolism, genotoxicity, 

biomarkers of exposure 

—Group C: “possible human carcinogen” 

• IARC (1996) 

—Did not include the epidemiology studies of Kilian et al. (2001), 

Yan et al. (2002) 

—Did not include animal cancer studies 

—Did not include several recent studies on metabolism, 

genotoxicity, biomarkers of exposure 

—Group 3: “not classifiable as to carcinogenicity in 

humans” 


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TNT: Summary of Evidence 

• Humans 

—Not adequately studied 

—Suggestion from case reports and controlled 

studies of liver cancer & leukemia 

• Animals 

—Rare urinary bladder tumors in female rats 

—Leukemias/malignant lymphomas of the spleen 

in female mice 

• Other relevant evidence 

—Genotoxicity of TNT & its metabolites 

—Structural similarity to the carcinogens 

2-nitrotoluene, and 2,4- and 2,6-dinitrotoluene

2,4,6-trinitrotoluene (TNT) - OEHHA

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